A comprehensive study of fragmentation pathways of 15-membered azalide macrocycles using electrospray ionisation with multistage mass spectrometry (ESI-MS(n)) is presented in this work. Hydrogen/deuterium (H/D) exchange experiments and high-resolution mass spectrometry were used to investigate the proposed fragmentation pathways. In addition, the fragmentation patterns of sodium adduct ions [M+Na](+) of the macrocycles were also investigated as the presence of an alkali metal interacting with the aglycone ring influences the product-ion spectra.
Keywords: 15-Membered azalide aglycone; ESI-MS(n); Fragmentation; H/D Exchange; Macrolides; Sodium adducts.
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